Field of the Invention
The present invention relates generally to fiber optic cable sub-assemblies and methods of assembling and, more particularly, to fiber optic cable sub-assemblies including a strain relief device for attaching an end portion of a fiber optic cable to a circuit board.
Technical Background
Fiber optic cables are known for their ability to transmit data at faster rates than cables having electrical conductors. Typically, fiber optic cables have been used in telecommunication networks, data centers, private network and the like. However, with the increasing demand for high-speed data transmission for consumer electronic devices such as smart phones, tablets, laptop computers, digital cameras, video displays such as televisions and the like fiber optic cables are being considered for replacing conventional electrical cables for high-speed data transmission applications.
Consequently, new fiber optic cables are being developed for attaching and making optical connections with electronic devices such as host and client devices. For example, many consumer electronic devices have one or more Universal Serial Bus (USB) electrical ports for establishing an electrical connection with an external device. The latest USB specification (USB 3.0) supports a data rate of 5 Gb/s, which is ten times faster than the previous USB specification (USB 2.0), and this latest version is still backwards compatible with the USB 2.0. As fiber optic cable designs begin to migrate into this space to support faster data rates, they still must be backwards compatible with the installed base of USB ports. Active optic cable (AOC) assemblies allow the use of the optical fibers as the transmission medium between the connectors on the ends of the cable instead of the conventional copper wires; however, the optical signals conveyed by the optical fibers are converted into electrical signals (i.e., optical-to-electrical (O-E) conversion) and vice versa (i.e., electrical-to-optical (E-O) conversion) so that the connector has an electrical interface to be compatible with the installed base of consumer devices.
In other words, for an AOC fiber-optic cable to be connected to a USB port, it must be terminated with a USB electrical interface configured for transmitting electrical signals at the port connection. Unlike a fiber optic cable used for telecommunications that experiences relatively few connections and disconnections in a controlled environment, a fiber optic cable use for consumer applications will experience frequent connections and disconnections in a variety of environments. Consequently, the mechanical connection between the fiber optic cable and the connector that terminates the cable must be robust for the large number of mating/unmating cycles expected over its lifetime.
Conventional fiber optic cable assemblies typically employ a crimp band that is secured (i.e., crimped) to a crimp body disposed on the end portion of the fiber optic cable. Typically, the strength members of the fiber optic cable are exposed and disposed between a barrel of the crimp body and secured to the same using the crimp band for strain relieving the cable to the connector such that pulling forces on the cable are transferred to the connector housing so stress and/or strain is not transmitted to the optical fiber. Such conventional strain relief configurations can add considerably to the overall length of the connector housing and are not suitable for active optic cable (AOC) assemblies since the connector footprint is different. Consequently, there is an unresolved need for a strain-relief assembly for securing a fiber optic cable to a sub-assembly of an active optic cable assembly or the like in a quick, reliable and cost-effective manner.